JP2020153303A - Control device for internal combustion engine - Google Patents

Abstract

To provide a control device for an internal combustion engine capable of inhibiting engine speed from becoming lower than speed to be maintained during coasting deceleration.SOLUTION: A control device for an internal combustion engine mounted to a vehicle mounted with an automatic transmission coupled to a torque converter includes: timing delay amount setting means setting timing delay amount of ignition timing on the basis of input rotational frequency of the transmission; and ignition control means performing ignition of the internal combustion engine at ignition timing based on the timing delay amount and an operating state of the internal combustion engine or a traveling state of the vehicle. In the case where the internal combustion engine is in the deceleration state due to coasting of the vehicle, a lock-up clutch of a torque converter is in the disengaged state and fuel supply into a cylinder of the internal combustion engine is in the cut state, when ignition is started by the ignition control means along with resumption of fuel supply, the timing delay amount setting means temporarily executes reduction processing of reducing the timing delay amount or temporarily executes stop processing of stopping the setting of the timing delay amount.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for an internal combustion engine mounted on a vehicle equipped with an automatic transmission connected to a torque converter.

In Patent Document 1, the fuel is cut when the vehicle is decelerated in order to improve the fuel efficiency of the internal combustion engine, and the ignition timing is delayed (degraded) in order to reduce the torque shock when the fuel supply is restarted. Then, when a misfire is detected, a technique for returning the delayed ignition timing (returning the retard angle) is described.

Further, Patent Document 2 describes the engine speed when the conditions that the cooling water temperature is equal to or higher than a predetermined value, the vehicle speed is within a predetermined range, the predetermined shift position, and the fuel cut control is not being performed during idle operation are satisfied. A technique for controlling the ignition timing according to the rotation speed difference from the fuel return rotation speed for returning the fuel supply from the fuel cut is described.

JP-A-2002-213333 Japanese Unexamined Patent Publication No. 6-147080

However, as described in Patent Document 1, even if an attempt is made to return the retard angle after detecting a misfire, the engine speed may drop before the accumulated retard angle returns.
On the other hand, in the technique described in Patent Document 2, since the input rotation speed of the transmission is not taken into consideration, the engine rotation speed may exceed the input rotation speed of the transmission (rotation speed up). In addition, since the minimum maintenance speed is not taken into consideration, there is a possibility that the engine speed will drop.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device for an internal combustion engine capable of suppressing a decrease in engine speed below a speed to be maintained during coast deceleration. To do.

The internal combustion engine control device according to one aspect of the present invention is an internal combustion engine control device mounted on a vehicle equipped with an automatic transmission connected to a torque converter, and is ignited based on the input rotation speed of the transmission. With the ignition timing set based on the retard angle setting means for setting the retard angle amount of the timing, the operating state of the internal combustion engine or the running state of the vehicle, and the retard angle amount set by the retard angle amount setting means. The ignition control means for igniting the internal combustion engine, and the retard angle amount setting means, the internal combustion engine is in a deceleration state due to deceleration due to the coast running of the vehicle, and the lockup clutch of the torque converter is not engaged. When the fuel supply to the inside of the cylinder of the internal combustion engine is in the cut state and the fuel supply is restored due to the decrease in rotation of the internal combustion engine, the ignition control means ignites the fuel supply. Is characterized in that, at the time of starting, the reduction process for reducing the retard angle amount is temporarily executed, or the stop process for stopping the setting of the retard angle amount is temporarily executed.

According to the present invention, when the internal combustion engine is in the deceleration state, the lockup clutch is not engaged, and the fuel supply is in the cut state, when the fuel supply is restored, the retard angle amount reduction process is temporarily performed. By temporarily executing the execution or stop processing, it is possible to prevent the engine speed from dropping below the speed to be maintained during coast deceleration.

It is a system block diagram of the control device of the internal combustion engine which concerns on embodiment of this invention. It is a block diagram which shows the configuration example by extracting the main part related to the retard angle setting of the engine control unit shown in FIG. It is a timing chart which shows the normal operation during the coast deceleration of an AT car. It is a timing chart for demonstrating the operation at the time of abnormality during coast deceleration of an AT car. It is a flowchart for demonstrating the required torque calculation operation at the time of coast which concerns on 1st Embodiment of this invention. It is a flowchart for demonstrating the correction retard angle amount calculation operation. It is a flowchart for demonstrating the ignition control operation. It is a flowchart for demonstrating the required torque calculation operation at the time of coast which concerns on 3rd Embodiment of this invention. It is a flowchart for demonstrating the required torque calculation operation at the time of coast which concerns on 4th Embodiment of this invention. It is a flowchart for demonstrating the required torque calculation operation at the time of coast which concerns on 5th Embodiment of this invention. It is a flowchart for demonstrating the required torque calculation operation at the time of coast which concerns on 6th Embodiment of this invention. It is a flowchart for demonstrating the required torque calculation operation at the time of coast which concerns on 7th Embodiment of this invention. It is a flowchart for demonstrating the required torque calculation operation at the time of coast which concerns on 8th Embodiment of this invention. It is a figure for demonstrating the set value of the map in the coast demand torque calculation operation which concerns on 8th Embodiment of this invention. This is for explaining the control device of the internal combustion engine according to the ninth embodiment of the present invention, and is a block showing a configuration example by extracting the main parts related to the retard angle setting of the engine control unit shown in FIG. It is a figure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a system configuration of an internal combustion engine control device according to an embodiment of the present invention. A gear-type transmission 3 is connected to the engine (internal combustion engine) 1 via a torque converter 2, and torque is transmitted from the crankshaft on the engine side to the AT input shaft 4. The torque converter 2 includes a pump impeller 5 directly connected to the engine 1, a turbine runner 6 that transmits driving force to a gear transmission 3, a stator (fixed wing) 7, and the like, and these are housed in one housing to circulate oil. are doing. Further, the torque converter 2 is provided with a lockup clutch 8 that mechanically directly connects the engine side and the transmission side, and is supplied to the release side of the lockup clutch 8 by a lockup hydraulic control valve (not shown). The hydraulic pressure and the hydraulic pressure supplied to the fastening side are controlled.

Then, the engine control unit 11 is provided with the rotation speed (rotation speed) of the engine 1 detected by the engine rotation speed sensor 9, the rotation speed (rotation speed) of the AT input shaft 4 detected by the AT input shaft rotation speed sensor 10, and the like. The detection signal is input. The engine control unit 11 calculates the corrected retard angle amount based on these detection signals, outputs the ignition signal to the ignition device 12, and controls the ignition timing.

FIG. 2 shows a configuration example by extracting the main parts related to the retard angle setting of the engine control unit 11 shown in FIG. The engine control unit 11 includes a coast required torque calculation unit 21, a required torque calculation unit 22 for each scene, a correction retard angle calculation unit 23, an ignition control unit 24, and the like. The engine rotation speed detected by the engine rotation speed sensor 9 and the AT input shaft rotation speed detected by the AT input shaft rotation speed sensor 10 are input to the coast demand torque calculation unit 21, and the coast is based on these rotation speeds. Generates and outputs the hourly required torque signal. Further, the required torque calculation unit 22 for each scene calculates and outputs the required torque signal for each scene. The correction retard angle amount calculation unit 23 calculates and outputs the correction retard angle amount based on these coasting required torque signals and the required torque signals for each scene. The combined portion of the required torque calculation unit 21 at the time of coasting, the required torque calculation unit 22 for each scene, and the correction retard angle amount calculation unit 23 corresponds to the retard angle amount setting means.

The ignition control unit 24, which acts as an ignition control means, ignites the ignition device 12 at the timing of the ignition timing determined by the operating state of the engine, the running state of the vehicle, and the corrected retard angle amount output from the corrected retard angle amount calculation unit 23. Output a signal.

FIG. 3 shows the normal operation of the AT vehicle during coast deceleration. If the brake is stepped on while the vehicle is running (brake switch is on), the vehicle speed decreases (in this example, from 50 km / h to 0 km / h), and the gear stage starts from 4th speed (4th) as the vehicle speed decreases. , 3rd gear (3rd) at time t1 and 2nd gear (2nd) at time t2. The lockup clutch 8 is released (non-engaged state) prior to this downshift (time t0).
The rotation speed of the AT input shaft 4 gradually decreases, but temporarily increases after downshifting. The engine speed decreases as the vehicle speed decreases, and gradually converges to a predetermined target engine speed (800 rpm in this example).

The fuel return is performed at the timing ta after the lockup is released. The control of the amount of retardation of the ignition timing delays the ignition timing (degradation) when the engine speed shown by the solid line is higher than the target engine speed shown by the broken line (between ta-tb and tc-td). , When the target engine speed is higher than the engine speed (between tb and tc), the ignition timing delay is returned (the retard angle amount is reduced). As a result, the engine speed converges to the target engine speed.

FIG. 4 shows the operation at the time of abnormality during the coast deceleration of the AT vehicle. If the input shaft speed (INPUT RPM) of the AT drops for some reason just before ta, the engine lowers the engine speed in order to respond to it, and the engine speed is retarded in an attempt to reduce the actual engine speed to that target speed. Increase the amount. As a result, ignition after refueling becomes worse, the engine speed starts to rise later, and in the area AA surrounded by the broken line, the engine speed cannot maintain the hydraulic pressure of the transmission, which affects the operability. It has dropped below 700 rpm.

In the present invention, the retard angle amount of the ignition timing at the time of fuel recovery is adjusted so that the engine speed does not drop after the fuel is returned even when the input shaft speed (INPUTRPM) of the AT drops as shown in FIG. ..

[First Embodiment]
FIG. 5 is for explaining the operation of the control device of the internal combustion engine according to the first embodiment of the present invention, and is a procedure for calculating the required torque at the time of coast calculated by the required torque at the time of coast 21 in FIG. Is shown. First, the engine control unit 11 determines whether or not the engine is running on the coast based on the on / off of the brake switch, the vehicle speed, the state of the gear stage, etc. (step S1), and if the engine control unit 11 is running on the coast, the lockup clutch 8 is not engaged. It is determined whether or not it is in the (non-lockup state) (step S14), and if it is in the non-engaged state, the target engine (ENG) rotation is determined from the AT input shaft rotation speed (INPUTPM) (step S2).
If it is determined in step S1 that the vehicle is not running on the coast (non-coastal driving), or if it is determined in step S14 that the vehicle is not in the non-fastened state (fastened state, that is, the lockup state), the flag F is set to "F = 1". (Step S3), and if "F = 1", set to "F = 0" (step S4).

In step S5, it is determined whether or not the fuel cut (FC) has been started, and if the fuel cut has been started, it is determined whether or not the fuel return has been started (step S6). If it is determined that the fuel recovery has been started (fuel injection is in progress after the recovery), the delay is started at the start of the recovery (step S7).
In the next step S8, it is determined whether or not the predetermined delay time ΔD has elapsed. When the delay time ΔD has elapsed, it is determined whether or not the initial flag “F = 0” (step S9). If it is determined that "F = 0", it is set to "F = 1" (step S10).

On the other hand, if it is determined in step S3 that "F = 1" is not (F = 0), and if "F = 0" is set in step S4, the fuel cut has not been started in step S5 (before the fuel cut). If it is determined that (injection is in progress), the fuel recovery has not been started in step S6 (fuel is being cut), or if it is determined in step S8 that the delay time ΔD has not elapsed, the step Move to S11 and determine whether the flag is "F = 1". Then, if it is not "F = 1", the calculated value of the required torque at the time of coast is set to an invalid value and returned (step S12). Further, when "F = 1" is set in step S11, when it is determined in step S9 that the initial flag is not "F = 0" (F = 1), and in step S10, the flag is set to "F = 1". If so, the calculation of the required torque at the time of coast is started (calculated value is updated) and returned (step S13). The required torque at the time of coast is calculated based on the difference obtained by subtracting the target engine speed from the actual engine speed. The larger the difference, the larger the required torque at the time of coasting.

FIG. 6 is a flowchart for explaining the setting of the correction retard angle amount performed by the correction retard angle amount calculation unit 23 in FIG. 2. First, the required torque at the time of coast calculated by the required torque calculation unit 21 at the time of coast is acquired (step S31), and then the required torque for each scene calculated by the required torque calculation unit 22 for each scene is acquired (step S32). Next, the target torque is calculated by adding the required torque at the time of coast and the required torque for each scene (step S33). If the required torque at the time of coast is an invalid value, the required torque at the time of coast is excluded from the addition target.
Next, the actual torque is calculated (step S34), and the target torque is divided by the actual torque to calculate the corrected retard angle amount (step S35).

FIG. 7 is a flowchart for explaining the ignition control performed by the ignition control unit 24 in FIG. 2. First, the basic ignition timing is calculated (step S41), and then the corrected retard angle amount calculated by the correction retard angle amount calculation unit is acquired (step S42). Next, the ignition timing is calculated by adding the basic ignition timing and the corrected retard angle amount (step S43). Then, the ignition signal is output to the ignition device 12 to ignite the engine 1 (step S44).

As described above, in the first embodiment, the corrected retard angle amount is corrected by making the calculated value of the required torque during coasting in the coasting required torque calculation unit 21 an invalid value during the delay time after the fuel is returned. The amount of correction retardation in the calculation unit 23 becomes smaller during the same delay time. In other words, a reduction process that reduces the amount of retardation is temporarily executed. Therefore, when the ignition timing in the ignition control unit 24 is the same delay time, the delay becomes small, so that the ignition after the fuel is restored is improved and the rotation drop can be suppressed.

[Second Embodiment]
In the second embodiment, the coast demand torque calculation unit 21 starts the coast demand torque calculation (valid calculated value that is not an invalid value) immediately after the fuel is returned without providing a delay time after the fuel is returned, but instead. The correction retard angle calculation unit 23 provides a delay time after the fuel is restored, and during the delay time, the correction retardation amount calculation process is stopped or the calculated value is limited, and the retard angle amount setting is stopped. Alternatively, a reduction process for reducing the amount of retardation is temporarily executed.
Since other configurations and methods are the same as those of the first embodiment, detailed description thereof will be omitted.
Even with such a configuration and method, substantially the same action and effect as those of the first embodiment can be obtained.

[Third Embodiment]
FIG. 8 is for explaining the control device of the internal combustion engine according to the third embodiment of the present invention, and is another calculation procedure of the required torque at the time of coast calculated by the required torque at the time of coast 21 in FIG. Is shown.
In the third embodiment, when returning from the fuel cut in coastal driving, the calculation of the required torque during coasting is started after the actual engine speed becomes equal to or less than the target engine speed.

Since the basic configuration and method are the same as those of the first and second embodiments described above, only the different parts will be described. That is, when it is determined in step S6 of FIG. 8 that the fuel return has been started (fuel injection is in progress after the return), it is determined whether or not the actual engine speed has once experienced a state of being equal to or lower than the target engine speed (step S21). .. Then, if it is experienced, it is determined whether or not the flag is "F = 0" for the first time (step S9), and if it is not experienced, it moves to step S11 and whether or not the flag is "F = 1". To judge.
According to such a configuration and method, the required torque calculation value at the time of coast becomes an invalid value until the actual rotation speed becomes equal to or less than the target engine speed. During that time, the correction retard angle amount in the correction retardation amount calculation unit 23 Can be temporarily executed to reduce the amount of retardation. Therefore, the same action and effect as those of the first and second embodiments can be obtained.

[Fourth Embodiment]
FIG. 9 is for explaining the control device of the internal combustion engine according to the fourth embodiment of the present invention, and is still another calculation of the required torque at the time of coast calculated by the required torque at the time of coast 21 in FIG. The procedure is shown.
In the fourth embodiment, when returning from the fuel cut in coastal driving, the required torque at the time of coast is calculated at the timing when the actual engine speed increases after the actual engine speed becomes equal to or less than the target engine speed. I am trying to start.

That is, in FIG. 9, it is determined whether the engine speed has increased after step S21 (step S22). Then, when it is determined that the flag has risen, it is determined whether or not the flag is "F = 0" for the first time (step S9), and if it is not experienced, the process proceeds to step S11 and the flag is "F = 1". Judge whether or not.
In this way, even if the calculation of the required torque at the time of coast is started after the actual engine speed becomes equal to or less than the target engine speed and the actual speed starts to increase, the same as in the first, second, and third embodiments. The effect is obtained.

[Fifth Embodiment]
FIG. 10 is for explaining the control device of the internal combustion engine according to the fifth embodiment of the present invention, and shows another calculation procedure of the required torque at the time of coast calculated by the required torque at the time of coast 21. There is. In the fifth embodiment, when the engine speed is increased before the actual engine speed becomes equal to or lower than the target engine speed when returning from the fuel cut in coastal driving, the engine speed is increased. Occasionally, the required torque calculation on the coast is started.

That is, in step S21 in FIG. 10, when the actual engine speed does not fall below the target engine speed, it is determined whether the engine speed has increased (step S22). Then, when the actual engine speed becomes equal to or lower than the target engine speed, or when it is determined that the engine speed has increased, it is determined whether or not the initial flag is "F = 0" (step S9). If the engine speed has not increased, the process proceeds to step S11, and it is determined whether or not the flag is "F = 1".
In this way, either when the actual engine speed becomes less than or equal to the target engine speed, or when the actual speed starts to increase even if the actual engine speed does not fall below the target engine speed. The calculation of the required torque at the time of coasting may be started.

[Sixth Embodiment]
FIG. 11 is for explaining the control device of the internal combustion engine according to the sixth embodiment of the present invention, and further another calculation of the required torque at the time of coast calculated by the required torque at the time of coast 21 in FIG. The procedure is shown.
In the sixth embodiment, the delay time provided after the fuel is restored in the coast demand torque calculation unit 21 is set longer as the amount of decrease in the rotation speed of the engine 1 per unit time at the time when the fuel supply is restored is larger. ..

That is, when setting the start delay for the correction of the ignition timing, the delay time is lengthened as the amount of rotational change at the time of fuel recovery is larger in the negative direction (steep downward) using the table.
For example, when the amount of rotation change is -2000 [rpm / s], the delay is 600 [ms], when the amount of rotation change is -1000 [rpm / s], the delay is 300 [ms], and the amount of rotation change is -500. When [rpm / s], the delay is set to 150 [ms], and when the amount of rotation change is −250 [rpm / s], the delay is set to 80 [ms].
In this way, by setting the delay time ΔDb according to the amount of change in the engine rotation, the setting of the delay time can be further optimized.

[7th Embodiment]
FIG. 12 is for explaining the control device of the internal combustion engine according to the seventh embodiment of the present invention, and is another calculation procedure of the required torque at the time of coast calculated by the required torque at the time of coast 21 in FIG. Is shown.
In the seventh embodiment, first, it is determined whether or not the vehicle is running on the coast (step S25), and if it is running on the coast, it is determined whether or not the lockup clutch 8 is in the non-engaged state (non-lockup state) (step). S51) In the non-engaged state, the target engine speed is the number of revolutions that is an intermediate half value between the input revolution speed of the transmission (INPUT PM) and the predetermined minimum maintenance speed of the engine 1 during shifting. Set to. When the target engine speed is equal to or lower than the predetermined lower limit of the target engine speed, the target engine speed is set to the lower limit of the predetermined target engine speed (step S26). Next, it is determined whether or not the fuel cut (FC) has been started (step S27), and if the fuel cut has been started, it is determined whether or not the fuel return has been started (step S28). If it is determined that the fuel recovery has been started (fuel injection is in progress after the recovery), the calculation of the required torque at the time of coasting is started (calculated value is updated) and the vehicle returns (step S29).

On the other hand, if it is determined in step S25 that the vehicle is not running on the coast (non-coast running), and if it is determined in step S51 that the vehicle is not in the non-concluded state (concluded state, that is, the lockup state), the fuel cut has been started in step S27. If it is determined that the fuel is not (injecting before fuel cut), or if it is determined in step S28 that the fuel recovery has not been started (fuel is being cut), the calculated value of the required torque during coasting is set to an invalid value. And return (step S30).
In this way, by performing feedback control with the target engine speed set to max (intermediate half value between INPUT PM and minimum maintenance speed, lower limit of target engine speed), the target engine speed does not drop even if INPUT PM drops. Therefore, that is, since the calculated value of the required torque at the time of coast does not drop, the amount of retardation of the ignition timing is reduced, and the engine speed drop can be suppressed.

[8th Embodiment]
FIG. 13 is for explaining the control device of the internal combustion engine according to the eighth embodiment of the present invention, and is still another calculation of the required torque at the time of coast calculated by the required torque at the time of coast 21 in FIG. The procedure is shown. Further, FIG. 14 is a diagram for explaining the set values of the map used in FIG.
In the eighth embodiment, the target engine speed is determined based not only on the input speed of the transmission but also on the input speed of the transmission and the gear ratio or the speed change stage of the transmission.

That is, as shown in FIG. 13, it is determined whether or not the vehicle is traveling on the coast (step S1), and if the vehicle is traveling on the coast, a map of the target engine (ENG) rotation speed corresponding to the current shift stage is selected (step S24). ). Then, the target engine (ENG) rotation is determined from the input shaft rotation speed (INPUT PM) of the AT based on the selected map (step S2). Other operations are the same as those of the first embodiment shown in FIG.
In this way, the map is referred to for each shift stage, and as shown in FIG. 14, the target engine speed is set closer to INPUT PM at lower speeds. By setting in this way, even if the INPUT PM drops in the low speed stage (3rd in the example of FIG. 14) where the rotation drop is likely to occur, the target engine speed does not easily drop, that is, the calculated value of the required torque at the time of coast is calculated. Since the engine does not drop, the amount of retardation at the ignition timing is reduced, and the engine speed can be suppressed.
In addition, in FIG. 14, the reason why there is no 2nd speed (2nd) and 1st speed (1st) is that the engine speed after returning to the fuel cut at the coast is in the region of the speed higher than the 2nd speed and 1st speed. Because.
Even with such a configuration and method, the same action and effect as those of each of the above-described embodiments can be obtained.

[9th Embodiment]
FIG. 15 is for explaining a control device for an internal combustion engine according to a ninth embodiment of the present invention, and is a configuration example in which a main part related to retard angle correction of the engine control unit shown in FIG. 1 is extracted. It is a block diagram which shows.
In the configuration shown in FIG. 2, a configuration is shown in which the portion including the required torque calculation unit 21 at the time of coast, the required torque calculation unit 22 for each scene, and the correction retard angle amount calculation unit 23 is the retard angle amount setting means. In that configuration, it has been explained that the required torque calculation unit 21 at the time of coasting or the correction retardation amount calculation unit 23 performs a processing operation so that the retard angle amount immediately after refueling is reduced. On the other hand, in the present embodiment, the portion in which the required torque calculation unit 21 at the time of coast, the required torque calculation unit 22 for each scene, the correction retard angle calculation unit 23, and the correction retardation amount limiting unit 25 are further combined is the retard angle amount. As a setting means, the processing of the required torque calculation unit 21 and the correction retardation amount calculation unit 23 at the time of coast does not include consideration that the correction retardation amount immediately after the fuel is returned is reduced, and the correction retardation amount limiting unit 25 is used. , The configuration is such that the amount of retard angle is limited when the predetermined conditions as described above are satisfied.
Even with a configuration in which a portion dedicated to the process of limiting the amount of retardation immediately after the fuel is returned is arranged in this way, substantially the same action and effect as the configuration shown in FIG. 2 can be obtained.

1 ... engine (internal engine), 2 ... torque converter, 3 ... gear type transmission, 4 ... AT input shaft, 5 ... pump impeller, 6 ... turbine runner, 7 ... stator (fixed blade), 8 ... lockup clutch, 9 ... Engine rotation speed sensor, 10 ... AT input shaft rotation speed sensor, 11 ... Engine control unit, 12 ... Ignition system, 21 ... Coast required torque calculation unit, 22 ... Required torque calculation unit for each scene, 23 ... Correction delay Angle amount calculation unit, 24 ... Ignition control unit, 25 ... Correction retard angle amount limiting unit

Claims (10)

A control device for an internal combustion engine mounted on a vehicle equipped with an automatic transmission connected to a torque converter.
A retard angle setting means for setting the retard angle amount of the ignition timing based on the input rotation speed of the transmission, and a retard angle amount set by the operating state of the internal combustion engine or the running state of the vehicle and the retard angle amount setting means. It is equipped with an ignition control means for igniting the internal combustion engine at the ignition timing set based on the above.
The retard angle amount setting means
The internal combustion engine is in a decelerated state due to deceleration due to the coast running of the vehicle.
The lockup clutch of the torque converter is not engaged and
When the fuel supply into the cylinder of the internal combustion engine is in the cut state,
When the fuel supply is restored due to the decrease in rotation of the internal combustion engine,
When the ignition control means starts ignition with the return of the fuel supply, the reduction process for reducing the retard angle amount is temporarily executed, or the stop process for stopping the setting of the retard angle amount is temporarily executed. A control device for an internal combustion engine. The internal combustion engine according to claim 1, wherein the reduction process is temporarily executed, or after the stop process is temporarily executed, the reduction process is canceled or the retard angle amount setting is restarted. Engine control device. The retard angle amount of the ignition timing by the retard angle amount setting means is set based on the target engine rotation speed and the actual rotation speed, in which the target engine rotation speed is set based on the input rotation speed of the automatic transmission. 2. The method according to claim 2, wherein every time when returning from the fuel cut in coastal driving, a reduction process or a stop process is executed once until the actual engine speed becomes equal to or less than the target engine speed. Internal combustion engine control device. Every time when returning from the fuel cut in coast driving, the actual engine speed is reduced or stopped until the actual engine speed becomes less than the target engine speed and the actual engine speed changes from a downward change to an upward change. The control device for an internal combustion engine according to claim 2, wherein the process is executed. In a state where the retard angle amount of the ignition timing is reduced or stopped by the retard angle amount setting means, the actual engine speed changes downward before the actual engine speed becomes equal to or less than the target engine speed. According to claim 4, when the actual engine speed changes from the state of being in the state to the change of the increase, the decrease process or the stop process is terminated when the actual engine speed changes from the state of the change to the increase. The control device for the internal combustion engine described. The control device for an internal combustion engine according to claim 1, wherein a reduction process or a stop process is executed until a predetermined time elapses from the return of the fuel supply. The control device for an internal combustion engine according to claim 6, wherein the predetermined time is set longer as the amount of decrease in rotation per unit time of the rotation speed of the internal combustion engine at the time when the fuel supply is restored is larger. .. The claim is characterized in that the target engine rotation speed is set to an intermediate half value rotation speed between the input rotation speed of the transmission and the predetermined minimum maintenance rotation speed of the internal combustion engine. 3. The control device for an internal combustion engine according to 3. When the target engine speed is equal to or lower than the predetermined lower limit of the target engine speed, the target engine speed is set to the lower limit of the predetermined target engine speed. The control device for an internal combustion engine according to claim 8. The control device for an internal combustion engine according to claim 3, wherein the target engine speed is set based on the gear ratio or gear of the automatic transmission and the input speed of the transmission.